My beloved original head-gasket has finally given up after 95K! miles on my 2000 S1 non VVC. My Elise is now in lots of bits feeling sorry for itself. The original plan was to bung a MLS gasket in and stitch it back up but now heavily considering the MEMS 2 143BHP VVC conversion and as I appeciate it's probably been covered 1001 times (albeit I'm struggling to find all the info in one place) I've yet to find anywhere that covers one of my biggest concerns, that being my Cobra 6422 alarm system.

How I see things is at the minute my Cobra 6422 alarm module is seemingly coded to my Lucas 5AS module which in turn is paired to my current non VVC engine ECU. Everything works fine off the Cobra alarm fob so the plan is to use my existing Cobra alarm which seems to decode the 5AS immobiliser then I need it to run the replacement VVC ECU.

Does anyone know anything about this and how do other VVC conversion get round this? Ideally I don't want to forefit my Cobra unit as it's got a Thatcham 1 certificate and I can see my insurers asking questions if they car goes on it being stolen and I'd rather not have to have to use the two button Rover fob to start my car after having already used to the Cobra one to turn the alarm off and open the door.

Is a simple and possible answer to program my current 5AS unit to the new (but used) VVC ECU? How is the Cobra alarm module coded to the Lucas 5AS? Will asking someone to pair my existing 5AS to my new VVC ECU accidentally uncode the Cobra alarm which seems to use an encrypted key sent via a wire to the 5AS? and can my non VVC 5AS unit be coded to a MEMS 2 VVC ECU?

Any tips or heads up will be appreciated and where possible I'll keep the thread updated with my other findings for anyone else wondering the same.

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I started with many K-series engines, then got a Lotus chassis in the Satria GTi, now I've put them together and got an Elise